In the current wireless communications field, the common public radio interface (CPRI) is a communications interface standard between a building baseband unit (BBU) and a radio remote unit (RRU) in a radio base station device in the current wireless communications industry. CPRI interfaces are interconnected by using a special CPRI network. An existing method for CPRI networking mainly includes: performing point-to-point optical fiber transmission connection by using a direct-connect fiber; or performing radio frequency or baseband interconnection between a BBU and an RRU by using a special CPRI switching device. However, for performing point-to-point transmission connection by using an optical fiber, multiple direct-connect fibers are required to connect CPRI ports of multiple RRUs to CPRI ports of multiple BBUs. As a result, networking costs are excessively high and a network layout is inflexible. In contrast, for performing interconnection between a BBU and an RRU by using a special CPRI switching device, a specially-developed CPRI switching device is required to implement an information exchange between the BBU and the RRU. However, the specially-developed CPRI switching device is not applicable to an existing transmission network, for example, a dedicated network needs to be laid out to perform data transmission, and transmission cannot be performed by using a standard Ethernet transmission network. Consequently, a layout of a dedicated network for data transmission increases difficulty and CPRI networking costs, and an operator cannot perform interconnection networking between a BBU and an RRU or between BBUs by using the existing Ethernet transmission network, resulting in waste of resources.
Based on the foregoing description, a potential solution is to directly switch a CPRI interface to an Ethernet transmission network, and transmit CPRI data by using the Ethernet transmission network. However, the inventor finds that, although CPRI data can be transmitted by using a 10G physical-layer interface and physical-layer medium by carrying the CPRI data in an Ethernet physical-layer data format at a physical layer, the foregoing CPRI data transmission process involves only transmission of an entire CPRI data frame, and only a CPRI data frame corresponding to a single service flow can be transmitted at a time. As a result, only point-to-point data transmission between an RRU and a BBU can be performed in the entire process, which limits networking flexibility, and cannot be applied to point-to-multipoint data transmission between multiple RRUs and multiple BBUs.